CG Board Class 7 Science Static Electricity textbook mcq , Fill in the blanks and question answers for students.
Choose the correct answer –
1. On rubbing two objects (a) and (b) if (a) attains negative (-) charge then (b) will have–
(a) negative charge (b) negative and positive charges both
(c) positive charge (d) none of these
2. Out of the following, which one can not be easily charged by friction?
(a) glass rod (b) ball of wool
(c) copper rod (d) balloon filled with air
3. Human body for electric current is –
(a) an insulator (b) sometimes a conductor / sometimes an insulator
(c) a conductor (d) none of these
4. When two objects are rubbed together, then they develop –
(a) opposite charge (b) same charge
(c) No charges (d) some times opposite some times same charge
5. Lightning conductors are made –
(a) of metal (b) of non-metal
(c) by painting the walls (d) of wood
Fill in the blanks –
(a) The materials that allow electric current to pass through them are called ……….. of electric current. [conductors ]
(b) Like charges………….each other, while unlike charges ………. each other. [repel , attract]
(c) The mechanism used to protect the buildings from lightning is called ………..[lightning conductor.]
(d) When two objects are rubbed with each the nature of the charges produced on them is …………[opposite]
Give reasons –
(a) When the television is switched on or off, a crackling sound is produced if a hand is placed on the screen of the television.
The rubbing of the hand against the screen generates static electricity.The discharge of static electricity between the hand and the screen produces the crackling sound.
Write the names of two conductors and two insulators for electricity.
Conductors: Copper , Aluminum
Insulators: Rubber , Glass
